Prior key boxes, of the casing and drawer type, have utilized a key-operated lock mechanism to lock the drawer in place. These locks are conventionally formed of "pot" metal, such as zinc alloy. In certain instances a thief has been able, with special tools, to apply an outward prying force on the drawer, to break certain parts of the lock to gain access to the interior of the key box. While it would be possible to strengthen the lock mechanism by forming the parts from steel, this would be very expensive.